Just picked up an older Triad 10" powered subwoofer for 5 bucks off of craigslist. Previous owner said that the subwoofer has no output other than an annoying hum through the subwoofer driver. I confirmed this to be true . Regardless of input the sub only makes the annoying hum. Subwoofer driver itself appears to be fine. There is about 4 or 5 volts dc present on the speaker wires with the driver unhooked. I did not find any shorted output transistors. Not sure if a home amplifier is like a car amplifier but the rail voltage looks a little funny to me. I have +63 volts and -40 volts on the rails. Does that sound right? I know in a car amp that those usually match but I really have no idea what to look for in a home amplifier. I would like to get this thing running strong again as it looks like a decent little unit but I could really use a hand being pointed in some directions to help me along with this repair. If anybody could be of some help I would greatly appreciate it.